Istio 101 : How Istio ServiceEntry relates to Kubernetes Services and Endpoints


Kubernetes "converts" its services and pods/endpoints into a ServiceEntry through Istio.
 
A service with two pods and two endpoints - 10.244.3.1, 10.244.3.2 -, will be mapped to a ServiceEntry - host / IP address endpoint -.
Endpoints represent the IP addresses that a service sends its requests to.

The "hosts" in the ServiceEntry Yaml file are associated with the service.

A ServiceEntry adds newly added services to the service registry - database of existing services in Istio -, this allows existing services to be able to access these newly deployed ones.

Below is an example of a service its endpoint and the resulting service entry:


We have two nginx pods and the service entry that allows access through the host "service1.default.svc.cluster.local" to the nginx applications.

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